^^ this ( I was typing while nkata posted )
Edit your first post to show 1.35v instead of 1.75v. Will save a bit of hassle
The Gigabyte boards I have used went through the same 1-2sec power on -> power off -> 1-2sec power on, etc... cycle was when the board wasn't happy with an overclock / wrong memory settings. But with you removing the cmos battery,etc... it rules that out.
I take it you've check the capacitors, etc... on the motherboard for damage & there isn't any ?
Only thing I could suggest is to get another psu from an online retailer to test the pc & return it within the 7 day DSR period. You'll lose around £20 in postage costs though.
Iv got a brand new psu coming later today thursday, ill post back after testing with it later. Thanks for the advice, and ya ill edit that first post...